peak charger

I'm thinking about getting the Duratrax I-Peak AC/DC Mini Pulse charger for $70.
Do you think this would b a decent charger for my AAA 700mah nimh batt. and my nicad pack? Costs have to be low, i'm not going over $75. The charger also has to b relatively small. Another other charger ideas?

I'm not sure how much they are in the states, but the versa-pulse charger by fma should be in that price range and is a nice peak charger as well.

[pgoelz]

FWIW, Dymond Modelsports in Oshkosh WI has the Simprop charger with their name on it for $109.

And for anyone needing a simple and cheap peak charger, my local hobby shop carries one caled the "Micro-Lader" that does 4-7 cells (rumor is that it will do 8 cells too) at 1, 2 or 4 amps. It is a peak charger, and is very small... about the size of a pack of cigarettes but thinner. Sorry, I'm at the office and it isn't, or I'd be more specific with the model.



------------------
Paul Goelz
pgoelz (at) eaglequest (dot) com
Piccolo web page: http://www.eaglequest.com/~pgoelz/piccolo1.html

Petn7:
For what it is worth:
I do remember looking at the duratrax chargers from tower hobby, and it looked like most of them fit the bill for charging NiCad's, NiMH, etc. The duratrax wound up being on my runner-up list (I can't remember why though). I settled on the Simprop charger from Hobby-Lobby for $128. I think the reason was because it could handle up to 28 cells, and I didn't want to ever have to buy another charger. As you might guess, I haven't had the need to charge 28 cells yet so....

I will say that I am really happy with the simprop charger and it is fairly easy to use despite the fact that the instruction manual is sketchy.

[pgoelz]

OK, now that I've taken a look at it, the charger I mentioned is the Micro Lader, by Multiplex. It is small and cheap... about US$35 and is a peak detecting charger. It does not have a voltage boost circuit, so it is limited to 4-7 cells. I was told by the hobby shop that it will successfully charge an 8 cell pack.... not sure about that, since even my 7 cell packs peak very close to the 12.5V available from a 12V battery.

It has a charge current selector (1, 2 or 4 amps), a START button, and three LED indicators.

It seems to work great...... except that it goes into "trickle" mode after peaking. It defines "trickle" as ~100 mA for the 1A charge, ~120 mA for the 2A charge, and ~200 mA for the 4A charge. So if you charge your Piccolo packs at 1A, you will continue to pump 100 mA through them after peak. I'm not sure this is a good idea.... anyone else have an opinion? It has another possible ideosyncracy too... it does not like shorted packs. I put my ammeter directly across the output.... and blew the 2A fuse in the meter! And this was in "trickle" mode.

BTW, it does not claim to detect the lower peak on a NiMh pack.

------------------
Paul Goelz
pgoelz (at) eaglequest (dot) com
Piccolo web page: http://www.eaglequest.com/~pgoelz/piccolo1.html

[This message has been edited by pgoelz (edited 11-14-2000).]

[This message has been edited by pgoelz (edited 11-14-2000).]

Hy Paul: What had happend to the fuse of your ammeter is normal. The way this small chargers works is closing a transistor (in this case a MOSFET) directly over the battery for a period of time. Due to the internal resistence of the battery nothing will happend, but when you applie the ammeter you will get 12,5V / 0 ohm = a lot of current. This type of chargers are cheap but they reduce the life time of the cell, because as we have said before the current is not continues but pulses. This pulses makes the battery to suffer internal mechanical stress (you can hear the noise that the battery makes when charging by taking it close to your ear). I agree that leave the battery in tricke mode at 100ma is not a good idea, we are already demanding a lot to them when charging at 1A (4 X C).
Best regards Pablo.


[This message has been edited by Mighty Bomb Jack (edited 11-14-2000).]

[This message has been edited by Mighty Bomb Jack (edited 11-14-2000).]

[pgoelz]

OOPS! Maybe this is not as good a charger as I thought. No wonder it didn't get very hot at 1A. I thought it used a linear regulator. Are you saying that it pulse width modulates in fast charge mode as well as trickle? I'll have to put the scope on it and look.

Guess I'll be ordering another Dymond Super Charger!



------------------
Paul Goelz
pgoelz (at) eaglequest (dot) com
Piccolo web page: http://www.eaglequest.com/~pgoelz/piccolo1.html